How does this work? Will these scratches and dust have to be in the noise profile or will NV automatically try to detect and remove the scratches and dust? If so, should the mechanism be trusted not to find false positives and damage the picture? I prefer NV to just remove noise and I fix dust and scratches with proper avisynth filters.

"Slow Shutter" mode for video containing repeated frames (more...)

Can we have more details, how does this work? Are the frames detected as repeated removed and replaced? I have videos with frames that are not duplicates that NV 4.0 said they are likely duplicates. Should I be worried?

How does this work? Will these scratches and dust have to be in the noise profile

Quite the opposite, it is best to not include them into the profiling area. That is also described in the user guide.

Lugarimo wrote:will NV automatically try to detect and remove the scratches and dust?

It will. And there are adjustments in that Dust and Scratches feature that allow you to control the way it works.

Lugarimo wrote:If so, should the mechanism be trusted not to find false positives and damage the picture?

It is pretty good in my opinion. I recommend to try it and see if you can trust it.

Lugarimo wrote:I prefer NV to just remove noise

That is fine too. Did you already try NV4? It should very easy to see there that all those new filter sections are really optional.

Lugarimo wrote:

"Slow Shutter" mode for video containing repeated frames (more...)

Can we have more details, how does this work? Are the frames detected as repeated removed and replaced? I have videos with frames that are not duplicates that NV 4.0 said they are likely duplicates. Should I be worried?

Nothing is removed nor replaced. That feature simply allows the noise filter to work more accurately in presence of repeated frames.

If NV says that some frames may be repeated then it is worth taking a closer look at those frames. Some components may in fact be repeating. For example, please see the second clip here. The useful content of the frame does change every frame, but the noise component doesn't change every frame. That is one of the cases of repeated frames (repeated noise in this case) where the Slow Shutter mode can help. You can see why in that example too. The case "Filtered not using Slow Shutter" corresponds to NV3 (or NV4 not using Slow Shutter), while "Filtered using Slow Shutter" clearly show this new feature of NV4.

If you do not have such kind of problems (of noise not being fully reduced in presence of repeated frames) then you probably do not need to use this feature. After all, it is optional and should be used only when it is needed. Hence I see no reasons for worries.

Is this the same high quality option of the last versions? I've always had them enabled by default.

No, it is a new feature too. The old High quality option did not change the speed so much. This new feature does in fact do much more work trying to discern the finest details to better preserve them. Sometimes that actually helps to get better visual results, but that depends on the clip. However the processing speed is quite reduced so it makes sense to run some tests on a small part of a clip before choosing one setting of that option or another. Otherwise you may spend much more render time without a significant improvement. But if you do see some improvement then you can decide to spend additional render time.

We added new examples showing the features that were not present in NV3 (Dust and Scratches, Slow Shutter). Showing the difference of the regular noise filter is a bit more tricky but we will probably add that later too.

Ok I have tested it out with appropriate settings and the result is a lot smoother with less details than v3.
I have the Y removal set to 50%, lower than the usual 60% from previous NV versions.
Do I need to now mess with the "Mix with the original" setting to compensate?

Also where is the high quality setting? Is it the slider with "slower - faster / lower - higher quality"?

Is there a point to using the "Adapt to changing noise" now? In every circumstance it brought annoying artifacts to the frame and I have it off by default.

The slow shutter setting I'm not sure about the usefulness of because I got much better results by tearing out all duplicates of the video myself and denoising (and making a VFR video afterwards).

I am not sure what is causing the difference but if you could prepare a small test case for v3 and for v4 and send it to support [at] neatvideo.com then we would check what makes the difference for you.

The quality setting is in the General tab. It is a different thing than the old high quality option.

"Adapt to changing noise" should be used only when it is needed by the clip, not as a default. That is specified in the user guide.

Regarding Slow Shutter, of course it is preferable to process a clip without repeated frames whenever you can do that. But if you have no control over those repeated frames then Slow Shutter mode can help. Besides, not all duplicates are the same and Slow Shutter knows the difference between exact copies, almost exact copies and frames with repeating noise. They all require different treatment.

It's a private video so I cannot which sucks because I cannot reproduce this on other clips. Ironically, on some other clips it doesn't remove enough noise as v3 would.
Basically I think it is being too aggressive with this one and oversmoothing. What would one do in this situation? Lowering the Y removal doesn't seem to make much difference in v4. Do I need to use "Mix with original" to retain some texture? Or maybe disable spatial removal altogether? This video has light noise.

"Adapt to changing noise" should be used only when it is needed by the clip, not as a default. That is specified in the user guide.

So what's so different about this in v4 that it's off by default? In v3 I left it on by default and it always worked well.

I looked at the user guide but I skimmed it. By the way, you repeated a description of the same new feature twice in the guide, I think it was the dust removal one.

Also, can I have the video of that woman in the chair from your examples page? The original not the compressed. Thanks.

If i understand properly your post, either you found that v4 doesn't remove as mush noise as v3 (but what about details ?), either it's too agressive and remove too much details.
Finaly, until now, for you, v3 gives better results than v4, if i understand properly ?

Lugarimo wrote:So what's so different about this in v4 that it's off by default? In v3 I left it on by default and it always worked well.

As far as I remember, there were no changes in the way that option works in v4 vs v3. It is possible that the difference is caused by the specifics of the clip you work with now. Some clips may have certain compression-related peculiarities that may trip the adaptive function, which may lead to less accurate noise reduction. For example, if the noise properties significantly vary from one frame to another then adaptive may potentially make inaccurate adjustments. If you want to check the exact cause then we will need a reproducible test case - a clip, noise profile and filter preset. We will check the clip for those issues in the first place and then will run the render to see how the filter and adaptive actually behaves. It is likely that it behaves the same in v3 and v4.

NV4 with adapt off produces similar results ot NV3 with adapt on. Turning adaptive denoising in NV4 retains more unwanted noise like in these screenshots. Why is this?
It does seem to retain details in other parts though which is why I dont know whether or not to keep it on or ditch NV4 and keep using NV3.

So far our findings were simple: the problem in NV4 was caused by using an inaccurate noise profile that was not a good start for Adaptive to work correctly. Once we re-built the noise profile, the problems went away. The same clip was filtered without leaving the residual noise that was left in when using the inaccurate noise profile.

NV4 either removes too much or too little noise. Having the spot removal and slow shutter on at the same time created random blotches of smudging on some frames and removed parts of legitimate objects. Turning slow shutter off fixed this for the most part but some problems still persisted. Turning removal down to 100% alleviated most of them but now most spots and scratches are faded rather than removed.
Honestly, using Avisynth spot removal is a much better choice than bothering with this.

On top of all this, NV4 is 3 times slower than NV3 so what's the advantage here?

Anyway... please check out the screenshots and let me know if you want the source footage and NFP/DNP files if you think this is fixable. Because I'm close to asking for a refund.